Regenerative furnace apparatus having flue gas separators



H. S. HALL Nov. 15, 1955 REGENERATIVE FURNACE APPARATUS HAVING FLUE GAS SEPARATORS Filed March 15, 1951 2 Sheets-Sheet l 5 ,1 4 4. I n I Z I v I 3 r 0 a T I a L. III M 1 u 1 E {L111} N a M E HHIHU R I I9 5 I Z 4. 8 6 e 4 4 z 4 3 A 9 R 0 I M 4 m 4 m 3 A h m Pll II W I 7 !N|| w z m z C 0 M 5 P w J 5 W. A I 3 Z 9 8 4. 4 5-; u n R w A WM--- m w m m 6 M m A H IO INVENTOR. HENRY S. HALL BY ATTORNEY H. S. HALL Nov. 15, 1955 REGENERATIVE FURNACE APPARATUS HAVING FLUE GAS SEPARATORS Filed March 15, 1951 2 Sheets-Sheet 2 PRECIPI TATOR PRECIPITATOR INVENTOR. HENRY S. H ALL ATTORNEY United States Patent REGENERATIVE FURNACE APPARATUS HAVING FLUE GAS SEPARATORS Application March 15, 1951, Serial No. 215,717

1 Claim. (Cl. 263-15) This invention relates to'furnace control apparatus, and more particularly to apparatus for controlling the flow of hot gases from furnaces of the regenerative type.

The gases discharged from certain types of regenerative furnaces, viz. open hearth steel furnaces, carry considerable quantities of foregin matter in the form of fine dust-like particles. The resultant atmospheric pollution has resulted in a demand for an apparatus which will remove these particles from the gases before they escape into the atmosphere. While precipitators of various types are known which will operate in an efiicient manner to remove dust from gases at somewhat elevated temperatures, such precipitators cannot withstand the very high temperatures at which gases are ordinarily discharged from open hearth furnaces and the like. Consequently, no satisfactory solution to the problem has been available heretofore.

It is accordingly one object of the invention to provide means whereby the precipitator can be protected from excessively high temperatures.

With these and other objects in view, as will be apparent to those skilled in the art, the invention resides in the combination of parts set forth in the specification and covered by the claims appended hereto.

In accordance with the invention in its preferred form, there are provided two furnace regenerators and two ejectors, the ejectors being connected to the respective regenerators. Air is supplied under pressure to each ejector, and means is provided whereby this air may serve either as ejector air to withdraw hot gases from the corresponding regenerator or as combustion air which will flow inwardly through the regenerator to the furnace. The mixture of hot gases and ejector air discharged from the ejectors is delivered to a precipitator, additional cooling air being admitted to the ejectors as required to reduce the temperature of the mixture and prevent damage to the precipitator. A third ejector is preferably provided to withdraw the cleaned gas from the precipitator and to control the pressure therein.

Referring to the drawings illustrating one embodiment of the invention and in which like reference numerals indicate like parts,

Fig. 1 is a side elevation of certain furnace control apparatus;

Fig. 2 is a top plan view of the apparatus; and

Fig. 3 is an elevation taken as indicated by the arrow 3 in Fig. 1.

As shown in Fig. 1, there is provided a furnace 10, which may be an open hearth steel furnace, with two vertical regenerators 11 and 11' at its opposite ends.

2,723,842 Patented Nov. 15, 1955 The upper ends of the regcnerators are connected to the inlet chambers 12 and 12' of two upright ejector tubes 14 and 14' respectively. These tubes are of Venturi shape and they are provided adjacent their throats with slidable dampers 15 and 15. Upwardly extending nozzles 16 and 16 are mounted in the chambers 12 and 12' respectively. These nozzles are connected by a horizontal duct 18, the central portion of this duct being divided by a horizontal partition 19 into an upper ejection air passage 20 and a lower combustion 'air passage 21. An ejection air fan 23, driven by a motor 24, delivers air through a duct 25 to the upper passage 20. A combustion air fan 27, driven by a motor 28, delivers air through a duct 29 to the lower passage 21. Vertically slidable dampers 31 and 31' are mounted within the duct 18 adjacent the opposite ends of the partition 19.

With the parts as so far described, the combustion air fan 27 may be used to supply air inwardly through either of the regenerators to support the combustion of the fuel in the furnace 10 in known manner, while the ejection air fan 23 supplies air for the withdrawal of hot gases outwardly through the other regenerator and the ejection of these gases to the atmosphere. Thus with the damper 15 open, the damper 15 closed, the damper 31 lowered, and the damper 31' raised, the combustion air from the passage 21 will flow through the nozzle 16' and thence downwardly through the regenerator 11', which heats the air, to the furnace 10; At the same time, the ejection air from the passage 20 will flow through the nozzle 16 and thence upwardly through the Venturi tube 14, drawing hot gases upwardly from the furnace through the regenerator 11, which will be heated by the gases. When the flow through the furnace is to be reversed, after an appropriate interval of time, the damper 15 will beclosed, the damper 15' opened, the damper 31 raised, and the damper 31' lowered. The combustion air will then flow downwardly through the regenerator 11, While the ejection air will flow through the nozzle 16 and Withdraw hot gases upwardly through the regenerator 11'. The fan 27 will be suitably adjusted to supply air at the rate required for efficient combustion of the fuel, and the fan .23 will be suitably adjusted to supply air at the rate required to maintain the pressure within the furnace 10 at a desired value i The hot gases which are discharged by the two Venturi tubes 14 and 14' alternately may be greatly contaminated with entrained fine solid particles of ash, slag, and the like, and cleaning of these gases may be required in order to avoid excessive pollution of the atmosphere. For this purpose there is provided a precipitator 33 of any suitable type, several forms of which are known. Some of these precipitators employ electrostatic charges to attract the fine particles, While others employ ultrasonic vibrations to agglomerate the particles and remove them from the gas stream, and still others employ water sprays or the like to wash the particles from the gas. The precipitator 33 as shown is mounted at a somewhat higher elevation than the duct 18 and equidistant from the two Venturi tubes 14 and 14' These tubes have extensions 34 and 34 respectively mounted on their upper ends, these extensions being connected to one another by a horizontal cross-over pipe 35. A duct 36 connects the central portion of the pipe 35 to one end of the precipitator 33. The other end of the precipitator is connected to the lower end of an upright Venturi tube 38 which forms an ejector. An upwardly directed nozzle 39 is mounted within the tube 38, this nozzle being supplied with air through a pipe 40 leading from a fan 42 driven by a motor 43. The upper portions of the extensions 34 and 34 are provided with normally. closed dampers 45 and 45 respectively, and the end portions of the cross-over pipe 35 are provided with normally open dampers 46 and 46'. In order that the temperature of the gases entering the precipitator may be controlled, the chambers 12 and 12' are provided with inlets 48 and 48' respectively for the admission of relatively cool air directly from the atmosphere, under the control of dampers 49 and 49' respectively.

The operation of the invention will now be apparent from the above disclosure. With the various dampers adjusted as shown in Fig. 1, the combustion air supplied by the fan 27 will be discharged through the nozzle 16', then flow downwardly through the regenerator 11 to absorb heat therefrom, and thence enter the furnace 10. The ejection air supplied by the fan 23 will be discharged through the nozzle 16 and create a suction which will draw hot gases upwardly through the regenerator 11, thereby heating the said regenerator. The mixture of hot gases and air will travel upwardly through the tube 14, thence through the cross-over pipe 35 and the duct 36 to the precipitator 33, which will remove the fine particles of solid material from the gases. The cleaned gases will then travel upwardly through the Venturi tube 38 to atmosphere, under the influence of the air current supplied by the fan 42 and discharged upwardly through the nozzle 39. The damper 49 will be held open sufficiently to admit cool air to the chamber 12 as required to prevent an excessive temperature in the gases entering the precipitator 33. To reverse the gas flow through the furnace after a suitable interval of time, the dampers 1S and 49 will be closed, the dampers 15' and 49' will be opened, the damper 31 will be raised, and the damper 31 will be lowered. Thereupon the combustion air from the fan 27 will flow downwardly through the regenerator 11 to the furnace, while the ejector air from the fan 23 will withhdraw hot gases upwardly through the regenertor 11' and deliver them, mixed with cool air, to the precipitator 33. The fan 27 will be suitably controlled to provide the correct flow of air for combustion of fuel in the furnace. The fans 23 and 42 will be suitably controlled to maintain the desired pressure conditions in the furnace 10 and the precipitator 33 respectively. If for any reason it becomes necessary or desirable to take the precipitator out of service temporarily or otherwise, the dampers 45 and 45' will be opened and the dampers 46 and 46' will be closed. The hot gases will then be discharged directly to the atmosphere through the extension tubes 34 and 34' alternately.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent is:

An apparatus for use with an industrial furnace having two regenerators each communicating with a respective end of the furnace, comprising: an upright ejector tube connected to each regenerator, a damper associated with the lower portion of each ejector tube to control gas flow therethrough, an ejector nozzle mounted in each ejector tube and directed upwardly therein, a horizontal duct connecting the ejector nozzles, a horizontal partition dividing the duct into an upper portion and a lower portion, an ejection air fan connected to one such portion of the duct, a combustion air fan connected to the other such portion of the duct, a damper at each end of the said portions of the duct for permitting one end only of each of the portions to be open, a horizontal cross-over pipe connecting the ejector tubes in portions above the dampers associated therewith, a precipitator connected to the central portion of the said cross-over pipe, an upright ejector stack attached to the gas outlet of the precipitator, an ejector nozzle mounted in the last-mentioned ejector stack and directed upwardly there in, a fan connected to the last-mentioned ejector nozzle, a damper mounted in each end of the cross-over pipe adjacent the connection thereof to the first-mentioned ejector tubes, a damper mounted in each of the firstmentioned ejector tubes in an upper portion above the connection of the cross-over pipe thereto, and a damper connected to each of the first-mentioned ejector tubes located adjacent its respective ejector nozzle for opening the ejector tube to the atmosphere by a predetermined amount.

References Cited in the file of this patent UNITED STATES PATENTS 1,012,488 Wedge Dec. 19, 1911 1,040,460 Taylor Oct. 8, 1912 1,310,455 Tainton July 22, 1919 1,811,459 Dyrssen June 23, 1931 1,835,210 Dyrssen Dec. 8, 1931 1,848,185 Mawha Mar. 8, 1932 1,900,397 Isley Mar. 7, 1933 2,042,475 Meharg et a1 June 2, 1936 2,477,420 Rhoades July 26, 1949 

